I. Field
The present invention relates generally to content delivery in network environments, and more particularly, to methods and apparatus for optimum file transfers in time-varying network environments.
II. Description of the Related Art
The distribution of content (data) to a large number of terminals (subscribers) in a wireless network is a complicated problem. For example, wireless networks cover large geographic regions, and the type of network coverage and/or available services may be different for each region. Therefore, delivering content to mobile devices that are moving from region to region requires an efficient delivery system that conserves network resources while providing device users with the content they desire.
Multi-user diversity is an important factor in wireless data networks. Typically, such diversity is used to achieve better spectral efficiency. However, from an application layer point of view, the results of such diversity may be inherent variability in the data rates allocated to users in such a network. Congestion control schemes typically used in the transport control protocol (TCP) were designed for wired networks. However, the loss and variability of a wireless channel causes the TCP protocol to re-transmit content frequently and thus waste bandwidth.
Typically, a conventional system attempts to solve this problem by making small changes to the TCP protocol in an attempt to handle loss and variability. However, the underlying Windows-based flow control scheme is flawed in such a time-varying environment and cannot make significant performance improvements.
Therefore, what is needed is a system that provides efficient file transfers in a time-varying wireless network. The system should operate to provide an adaptive rate-based protocol that controls the re-transmission of content so that network resources and bandwidth are conserved.